Engine Rebuild

[Bloodman324]

Hey guys, just recently bought myself another 720, Its an 81, same year as my truck and has the same engine, but its a manual choked carb and has the 5-speed manual transmission. I am planning on rebuilding the engine myself, because it smokes like a mofo and needs rings badly, I'm new to this and I found a kit, but it has options of .020 and .040 size of the rings and pistons, how do I tell what size I need to get?

[Bloodman324]

Oh and the same question for the main bearing and the rod bearing

[ProteanCarnage]

.020" is the amount in inches that is over the factory size.

If you are getting new pistons you might be honing the boring the cylinder, or it may have been done in the past. You must measure the walls and then subtract the factory size to find out what oversize you need. (A new engine will be STD or .00" pistons + rings, if you bore it down .025", you will need .025" sizes)